It’s funny you should bring this up—I was just thinking about this last night. I was washing dishes, and for some reason I started thinking about the episode of Star Trek where Starfleet Command wanted take Lt. Cmdr. Data apart to see how he works. The rest of the episode is a debate as to whether Data was ‘alive’ or not. If I were in that situation, I would argue that Data is alive because he is sentient—he is aware of his own existence. So, extrapolating that one step further, I guess your hypothetical cyborg is still human because his memories come from a human brain. Even though every last part of the body is replaced, the cyborg is derived from a human and is therefore at least ‘of human origin’.
